Work will be carried out on two projects. First, we will attempt to refine further techniques for detecting very small amounts of antigens and antibodies. Such techniques will then be used to identify type- and group-specific virus-coded antigens. The basic technique will be to react antiviral antibodies with extracts of infected radioactively labeled cells. Antigen-antibody complexes will be collected on cells of staphylococcus A. Following their dissociation, precipitated antigens will be quantitated by spectrophotometric analysis of autoradiograms of SDS-polyacrylamide gels in which they had been electrophoresed. We will be looking for antigens that are precipitated by homologus, but not by heterologous antisera; these will be type-specific antigens. We will also be looking for antigens that are precipitated equally well by homologous and heterologous antisera; these will be group-specific antigens. Attempts will then be made to isolate type- and group-specific antigens for radioactive labeling with 125I for use in radioimmunoassays. Second, we will prepare monoclonal antibodies to the ten polypeptides coded by reovirus. Mice will be infected with reovirus and hybridomas prepared from the spleen cells and 2-thioguanine-resistant myeloma cells. Supernatants of the resulting hybridomas will be tested for the ability to immunoprecipitate reovirus-coded polypeptides from extracts of infected cells. Cloning will be carried out either in vitro or in vivo, that is, by intraperitoneal injection and conversion to the ascitic form.